Optimization of laser powder bed fusion process for hydrogenated-dehydrogenated titanium alloy powders

Additive-manufactured titanium alloys are used in industries such as medical and aerospace due to their exceptional mechanical properties and corrosion resistance. However, the high cost of spherical powders limits their widespread adoption. In contrast, hydrogenation-dehydrogenation (HDH) titanium alloy powders are more cost-effective and can help mitigate this issue. However, due to their irregular shape, these powders exhibit poor processability in laser powder bed fusion (LPBF). This study optimizes the LPBF process parameters for HDH titanium powders and examines their effects on the microstructure, density, mechanical properties, and surface roughness of titanium alloys in the additive manufacturing process. Results from orthogonal experiments show that scanning speed has a significantly greater impact on the tensile strength and elongation of titanium alloys than laser power. Further analysis revealed that an optimal combination of laser power and scanning speed (180W-1000mm/s) can achieve dense forming of hydrogenated-dehydrogenated titanium powder (density of 99.996%), while delivering high mechanical performance (tensile strength of 1364.33 MPa, elongation of 6.8%) and low surface roughness (Ra = 0.823 μm). Microstructural analysis shows that higher cooling rates effectively refine the grain structure and enhance the mechanical properties of the material, although they also lead to increased internal stresses, which affect the material’s plasticity. Digital Image Correlation (DIC) and fracture analysis further reveal the deformation resistance and fracture modes of hydrogenated-dehydrogenated titanium alloys, showing that under suitable processing conditions, the material not only exhibits excellent mechanical performance but also effectively mitigates brittle fracture during deformation.